Leukotrienes such as leukotriene C.sub.4 (LTC.sub.4) and leukotriene D.sub.4 (LTD.sub.4) which participate in the onset mechanism of allergy are biosynthesized from arachidonic acid by the action of 5-lipoxygenase.
It has recently been made evident that leucotrienes relates not only to the onset of allergy, but also to the onset of other pathological conditions including nephritis, hepatis, leumatism and gastric ulcer.
Accordingly, it has been a subject of investigation to find substances inhibiting biosynthesis of leucotrienes thereby being effective in the therapy of these diseases. Discovery of substances having anti-ulcer activities against gastric and other ulcers has also been another subject.
We synthesized a variety of isoprenoid derivatives and made extensive studies on 5-lipoxygenase-inhibiting activities and anti-ulcer activities of these compounds. As a result of these studies we have found that the isoprenoid derivatives according to the present invention possess a high 5-lipoxygenase-inhibiting activity and a potent anti-ulcer activity. The invention has been completed on the basis of the finding. The 5-lipoxygenase inhibitory isoprenoid derivatives of the invention inhibit the biosynthesis of leucotrienes thereby being useful in the therapy of nephritis, hepatitis and rheumatism as well as asthma and rhinitis which are allergic diseases.
Furthermore, the isoprenoid derivatives of the invention which have an anti-ulcer activity are also useful in the therapy of gastric and other ulcers.
It is therefore an object of the invention to provide new isoprenoid derivatives and 5-lipoxygenase inhibitors and anti-ulcer agents containing same.